Abstract

The nucleotide and amino acid sequences of the nucleocapsid genes of two Iris yellow spot virus (IYSV) isolates from south-west Australia were determined and compared with those of three isolates from south-east Australia and 11 from elsewhere. Phylogenetic analyses revealed three distinct clades. The first contained a single isolate from Slovenia. The second and largest contained 11 isolates, five from Australia, four from Japan and one each from Israel and the Netherlands. The third included three isolates from Japan and one from Brazil. Genetic diversity did not correlate with original host species or geographical location from which an isolate came. Based on the sequence data presented, the five Australian isolates and four from Japan share a recent common ancestor. Lack of diversity among the local isolates, despite their origins in geographically distant locations, suggests that IYSV did not originate within Australia.